Accession Number : AD0634136

Title :   MECHANISMS OF EROSION OF TITANIUM BORONITRIDE ROCKET NOZZLES.

Descriptive Note : Technical rept.,

Corporate Author : ARMY MATERIALS RESEARCH AGENCY WATERTOWN MASS MATERIALS ENGINEERING DIV

Personal Author(s) : Wong, Anthony K. ; Brown,James

Report Date : MAY 1966

Pagination or Media Count : 33

Abstract : Four rocket nozzles with throat diameters varying from 0.71 to 2.0 inches were fabricated from titanium boronitride compacts. This newly developed material was formed from titanium and boron nitride powders utilizing high compaction pressures and high reaction temperatures. Two compositions were investigated. Test firings of these nozzles were carried out in solid propellant static test rocket engines utilizing aluminized propellants with theoretical flame temperatures of 5500, 5600, and 6400 F. Post test analysis revealed the presence of cracks attributable to thermal shock and processing deficiencies. The erosion encountered varied from negligible to extremely severe. In the most severe case, the primary mechanism of erosion was established to be oxidation and conversion of the higher melting temperature constituents into a lower melting temperature oxide, followed by melting and removal from the nozzle contoured surface under the action of shearing stresses exerted by the hot flowing propellant exhaust gases. However, with the 5500 and 5600 F propellant, the mechanism of erosion was principally one of mechanical abrasion. Under limited conditions, a firmly supported titanium boronitride rocket nozzle may prove to be satisfactory. (Author)

Descriptors :   (*ROCKET NOZZLES, *EROSION), SOLID PROPELLANT ROCKET ENGINES, REFRACTORY MATERIALS, CERAMIC MATERIALS, TITANIUM COMPOUNDS, BORON COMPOUNDS, NITRIDES, SOLID ROCKET PROPELLANTS, ALUMINUM, CAPTIVE TESTS

Subject Categories : Combustion and Ignition
      Solid Propellant Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE